THESE two animals have been denominated sloths, on account of
the slowness of their movements, and the difficulty with which they
walk. Though they resemble each other in many respects, they
differ, both externally and internally, by characters so marked, that
it is [150] impossible not to recognise them as very
distinct species. The unau, or two-toed sloth, has no tail, and
only two claws on all the feet. The aï, or three-toed
sloth, has a tail, and three claws on all the feet. The muzzle
of the former is longer, the front more elevated, and the ears more
apparent than those of the latter. Their hair is also
very different. The structure [151] and
situation of some parts of their viscera are likewise different. But
the most remarkable distinction is derived from this singular
circumstance, that the unau has forty-six ribs, and the aï only
twenty-eight, which shows them to be species very remote from each
other. This number of ribs, in the body of an animal so short,
is an excess or error of Nature; for no animal however large, has
such a number of ribs: The elephant has only forty, the horse
thirty-six, the badger thirty, the dog twenty-six, man twenty-four,
&c. This difference in the structure of the sloths
indicates a greater distance between these two species than between
the dog and cat, who have both the same number of ribs; for external
differences are nothing when compared to those which are
internal: The former may be regarded as causes, and the latter
as effect only. The interior frame of animated beings is the
foundation of Natures plan; it is the constituent form, and the
origin of a figure: But the external parts are only the surface
or drapery. How often have we not found, in the course of our
comparative examination of animals, that a very different external
appearance covered internal parts perfectly similar; and that, on the
contrary, the slightest internal distinction produced great external
differences, and changed the natural dispositions, powers, and
qualities of the animal? How many animals are armed, covered,
and adorned with ex- [152] crescent parts, whose
external structure corresponds exactly with others which are totally
deprived of such appendages? But this is not a proper place for
such nice disquisitions. We shall only remark, that, in
proportion as Nature is vivacious, active, and exalted in the monkey
kind, she is slow, restrained, and fettered in the sloths. From
a defect in their conformation, the misery of these animals is not
more conspicuous than their slowness. They have no cutting
teeth; the eyes are obscured with hair; the chops are heavy and
thick; the hair is flat, and resembled withered
herbs; the thighs are ill jointed to the haunches; the legs are too
short, ill turned, and terminated still worse: Their feet have
no soles, and no toes which move separately, but only two or three
claws disproportionally [sic] long, and bended downward,
which move together, and are more hurtful to their walking, than
advantageous in assisting them to climb. Slowness, habitual
pain, and stupidity, are the results of this strange and bungled
conformation. The sloths have no weapons either offensive or
defensive. They are furnished with no means of safety; for they
can neither fly nor dig the earth. Confined to a small space,
or to the tree under which they are brought forth, they are prisoners
in the midst of space, and cannot move the length of one
fathom in an hour.* They drag themselves up a tree with
[153] much labour and pain. Their cry and
interrupted accents they dare only utter during the
[154] night. All these circumstances announce
the misery of the sloths, and recall to our minds those defective
monsters, those imperfect sketches of Nature, which, being hardly
endowed with the faculty of existence, could not subsist for any
length of time, and have accordingly been struck out of the list of
beings. If the regions inhabited by the sloths were not desert,
but had been long occupied by men and the larger animals, these
species would never have descended to our times: They would
have been annihilated, as in some future period will be the
case. We formerly remarked, that every thing that possibly
could be, really did exist; of which the sloths are a striking
example. They constitute the last term of existence in the
order of animals endowed with flesh and blood. One other defect
added to the number would have totally prevented their
existence. To regard those bungled sketches as beings equally
perfect with others, to call in the aid of final causes to account
for such disproportioned productions, and to make Nature as brilliant
in these as in her most beautiful animals, is to view her through a
narrow tube, and to substitute our own fancies for her
intentions.

Why should not some animals be created for misery, since, in the
human species, the greatest number of individuals are devoted to pain
from the moment of their existence? Evil, it is true, proceeds
more from ourselves than from Nature.
[155] For a single person who is unhappy,
because he was born feeble or deformed, there are millions rendered
miserable by the oppression of their superiors. The animals, in
general, are more happy, because the species have nothing to fear
from individuals: To them there is but one source of evil; to
man there are two. Moral evil, of which he himself is the
fountain, has accumulated into an immense ocean, which covers and
afflicts the whole surface of the earth. Physical evil, on the
contrary, is restrained within very narrow bounds: It seldom
appears alone; for it is always accompanied with an equal, if not a
superior good. Can happiness be denied to animals, when they
enjoy freedom, have the faculty of procuring subsistence with ease,
and posses more health, and organs capable of affording greater
pleasure than those of the human species? Now, the generality
of animals are most liberally endowed with all these sources of
enjoyment. The degraded species of sloths are perhaps the only
creatures to whom Nature has been unkind, and who exhibit to us the
picture of innate misery.

Let us take a closer view of the condition of these creatures.
By the want of teeth, they can neither seize prey, nor feed upon
flesh or herbage. Reduced to the necessity of living upon
leaves and wild fruits, they consume much time in trailing their
bodies to the foot of a tree, and [156] still more in
climbing to the branches;* and, during this
slow and melancholy exercise, which sometimes lasts several days,
they are obliged to suffer the most pressing hunger. When
arrived [157] upon a tree, they never descend.
They cling to the branches, and devour successively the leaves of
every twig. They pass several weeks in this situation, without
receiving any drink. When they have rendered the tree entirely
naked, they still remain; because they cannot descend. In fine,
when the pressure of hunger becomes superior to the dread of danger
or death, being unable to descend, they allow themselves to tumble
down like an inanimated mass; for their stiff and inactive limbs have
not time to extend themselves in order to break the fall.

When on the ground, they are at the mercy of all their enemies.
As their flesh is not absolutely bad, both men and rapacious animals
go in quest of these animals. It appears that they do not
multiply fast, or, at least, if they produce frequently, it must be
in small numbers at a time; for they have only two paps. Every
circumstance, therefore, concurs to destroy them; and it is extremely
difficult for the species to support itself. But, though slow,
awkward, and almost incapable of motion, they are obstinate, strong,
and tenacious of life. They can live very long without
victuals of any kind.* They are
covered with thick, dry hair; and, being incapable of exercise, they
lose little by perspiration; and, though their food be meager, they
fatten by re- [158] pose. Though they have no
horns nor hoofs, nor cutting teeth in the under jaw, yet they belong
to the ruminating tribes, and have several stomachs. Hence the
quality of their food may be compensated by the quantity they take at
a time. What is still more singular, instead of very long
intestines, like other ruminating animals, their guts are very short
and small, like those of the carnivorous kind. This contrast
exhibits the ambiguity of Nature. The sloths are unquestionably
ruminating animals: They have four stomachs; and yet they want
every other character, both internal and external, which generally
belongs to animals of this class. There is still another
singularity in the conformation of the sloths: Instead of three
distinct apertures for the discharge of urine and excrements, and for
the purposes of generation, these animals have but one, which
terminates in a common canal, as in birds.

Moreover, if the misery resulting from a defect of sentiment be not
the worst of all, the pain endured by the sloths, though very
apparent, seems not to be real; for their sensations appear to be
blunt. Their calamitous air, their dull aspect, and their
reception of blows without emotion, announce their extreme
insensibility. This bluntness of sensation is farther
demonstrated, by their not dying instantly when their hearts and
bowels are entirely cut out. Piso, who made this
[159] cruel
experiment,* tells us, that the heart, after being separated from
the body, beat in a lively manner for half an hour; and that the
animal continued to contract its legs slowly, as commonly happens
during sleep. From these facts, this quadruped seems to
approach not only the turtle, but other reptiles which have no
distinct centre of sensation. All these beings may be said to
be miserable, but not unhappy: Nature, even in her most
neglected productions, always appears more in the character of a
parent than of a stepmother.

These two animals are peculiar to the southern regions of the New
Continent, and are no where to be found in the Old. We formerly
remarked, that the editor of Sebas cabinet was deceived when he
calls the tow-toed [sic] sloth, or unau, the sloth of
Ceylon. This error, which has been [160]
adopted by Klein, Linnaeus, and Brisson, is now more evident than it
was formerly. The Marquis de Montmirail has a live unau, which
was transmitted to him from Surinam: Those we have in the Royal
Cabinet were brought from the same place and from Guiana; and I am
persuaded that both species exist through the whole deserts of
America, from Brasil* to
Mexico. But, as they have never frequented the northern
regions, they could not pass from the one Continent to the
other. If these animals have sometimes been seen in the East
Indies, or on the coast of Africa, it is certain that they must have
been transported thither. They cannot endure cold; and they
likewise dread rain. The alternation of moisture and dryness
changes their fur, which has more the appearance of ill dressed hemp
than of wool or hair.

I shall finish this article with some observations communicated to me
by the Marquis de Montmirail, concerning an unau, or two-toed sloth,
which he fed three years in his menagerie: The hair of
the unau is much softer than that of the aï ..All that has
been said by travellers concerning the excessive slowness of the
sloths should, probably, be applied only the aï, or three-toed
species. The unau, though very heavy, and of an extremely
awkward gait, [161] mounted and descended the highest
tree several times in a day. It is in the evening and during
the night that he was most active, which made me suspect that he saw
very ill in the day, and that his eyes were of no use to him but in
the dark. I purchased this animal at Amsterdam. It was
fed with sea biscuit; and I was told, that, during the verdure of the
trees, it would require nothing but leaves. We have him leaves,
which he eat [sic] freely, when they were tender; but, as
soon as they began to dry, or were pierced by caterpillars, he
refused them. During the three years that I kept him alive in
my menagerie, his ordinary food was bread, apples, and roots; and his
drink was milk. He always laid hold, though with difficulty, of
what he wanted to eat, with his fore paws; and the difficulty
increased in proportion to the largeness of the morsel. He
seldom cried; his cry is short, and he never repeats it twice,
without a considerable interval. This cry, though plaintive,
has no resemblance to that of the aï, if it be true that the
aï is the sound of that animals voice. The
most natural situation of the unau, and which he prefers to all
others, is hanging on a branch, with his body turned downward.
He sometimes sleeps in this position, his fore paws being fixed to
the same point, and his body forming an arch. The strength of
his muscles is incredible; but it becomes useless to him when he
walks; for his [162] motion is constrained and
wavering. This structure alone seems to be the cause of the
animals slowness, which, besides, has no violent appetites, and
does not recognise those who take care of him.

SUPPLEMENT.

M. de la Borde remarks, that there are two species of these animals
in Cayenne, the one called the bashful sloth, and the other
the sheep-sloth. The latter is twice as long as the
former, and of the same thickness. He has long, bushy, whitish
hair, and weighs about twenty-five pounds. He throws himself
down upon men from the tops of trees, but in a manner so sluggish,
that it is easy to avoid him. He feeds during the day as well
as the night.

The bashful sloth, M. de la Borde remarks, has
black spots on his body, weighs twelve pounds, keeps always on trees,
and eats the leaves of the Surinam fig-tree, which are said to be
poisonous. The bowels of this sloth poison dogs, and yet the
flesh is good eating; but its use is confined to the common
people.

Both species produce only a single young, which they always
carry on their back. It is [163] probable,
though I am not certain, that the females bring forth on trees.
They feed on the leaves of the Brasilian
plumb-tree,* and of the Surinam fig. The two species are
equally common; but they are not frequent in the environs of
Cayenne. They sometimes suspend themselves by their claws on
branches of trees which hang over the rivers; and, when in this
situation, it is easy to cut the branch and make them fall into the
water; for they never quit their hold.

When ascending a tree, this animal carelessly stretches out one
of its fore pats, and fixes its long claw as high as it can
reach. It then heavily raises its body, gradually fixes the
other pat; and, in this manner, continues to climb. All these
movements are incredibly slow and languid. When kept in houses,
they always climb upon some post or door, and never choose to rest on
the ground. If a stick is held out to them when on the ground,
they lay hold of it, and mount to its top, where they firmly adhere
with their fore paws, and embrace the stick with their whole
body. They have a weak plaintive cry, which is heard at no
great distance.

From this passage, it is obvious, that the sheep-sloth is the same
with what we have called unau, or the three-toed sloth; and
that the bashful-sloth is the aï, or two-toed species.
[164] [Plate CCXII here] [Plate CCXIII
here] [Plate CCXIV here]

M. Vosmaër, an able naturalist, and superintendent of the Prince
of Oranges cabinet, has criticized two assertions in my history
of these animals. He remarks, that we ought to reject the
relation of M. de Buffon, when he tells us, that the sloths are
unable to descend from a tree, but allow themselves to fall down
like blocks.*

I advanced this fact on the authority of eye-witnesses, who assured
me, that they had sometimes seen the animal fall down at their
feet. The fact is farther supported by the testimony of M. de
la Borde. What I have said on this subject, therefore, ought by
no means to be rejected.

The second assertion is not equally well founded. I willingly
acknowledge my mistake, when I said that the sloths had no teeth, and
I thank M. Vosmaër for correcting this error.

Notes

* The sloths have no cutting teeth in either
jaw; but they have canine teeth and grinders. The fore legs are
much longer than the hind, and the claws are long. --- The two-toed
sloth has a round head, short projecting nose, ears like the human,
lying flat on the head, two long claws on the fore feet, and three on
the hind. The hair on the body is long and rough; in some parts
curled and woolly, in some, of a pale red above, cinereous below; and
in others, of a yellowish white below, and a cinereous brown
above. The length of that in the British museum, is eleven
inches; I believe it is a young one: It has no tail;
Pennants Synops. of quad. p. 321.

** The three-toed sloth has a burnt black
nose, a little lengthened, very small external ears, and eyes small,
black, and heavy. From the corner of each eye, there is a dusky
line. The colour of the face and throat is a dirty white.
The hair on the limbs and body is long, very uneven, and of a
cinereous brown colour. The tail is short, being a mere
stump. The legs are thick, long, and awkwardly placed.
The face is naked. There are three toes, and three very long
claws on each foot. The length of that in the British museum is
twelve inches; but it grows to the size of a middle sized fox;
Pennants synops. of quad. p. 319.

Aï, the Brazilian name of this animal, taken from its
plaintive cry a, i, which it often repeats, Hay,
according to Lery; and Hau or Hauthi, according to
Thevot. The Perillo ligero of Oviedo, and the
Haut of Nieremberg.

* Perillo ligero, sive canicula agilis,
animal est omnium [153] quae ignavissimum; nam adeo lente
movetur, ut ad conficiendum iter longum dumtaxat quinquaginta passus,
integro die illi opus sit.----In aedes translatum naturali sua
tarditate noventur, nec a clamatikone ulla aut impulsione gradum
accelerat; Oviedo in summario Ind. Occid. cap. 23. traduit
de lEspagnol en Latin par Clusius, Exotic. lib. 5.
cap. 16. Tanta est ejus tarditas ut unius diei spatio
vix quiquaginta passus pertransire posit; Hernand. Hist.
Mex.---The Portuguese have given the name of sloth to a
very extraordinary animal, which is of the size of an opossum.---The
hind part of its head is covered with a course mane, and its belly is
so gross that it sweeps the ground. It never rises on its legs,
and trails so slowly along, that in fifteen days it can hardly
accomplish the length of a stone-cast; Hist. des Indes, par.
Massé, p. 71. Descript. des Indes Occident. par
Herrera, p. 252.--- Tam lentus est illius gressus et
membrorum motus, ut quindecim ipsis diebus ad lapidis ictum continuo
tractu vix prodeat; Pison. hist. Bras. p.
322. Nota. This assertion of Piso, which he has
borrowed from Massé and Herrera, is much exaggerated.----This
is the most sluggish of all animals: It is needless to employ
greyhounds to overtake him; a tortoise is sufficient; Desmarchias,
tom. 3. p. 301, Nota. This is another
exaggeration.----They require eight or nine minutes to advance one
foot to the distance of three inches, and they move one after another
with equal slowness. Blows do not accelerate their pace.
I have whipt [sic] some of them, in order to discover whether
pain would give them any animation: But they seemed insensible,
and I was unable to make them move faster; Dampiers
voyage.---The sloths do not move fifty paces in a day. When
the hunter wishes to take one of them, he may proceed with his sport,
and, on his return, he will find the animal very little removed from
its former place; Voyage à Cayenne, par Binet, p.
341.-----This animal receives the epithet of courser, because he
requires a whole day to accomplish a quarter of a league; Hist. de
lOrenoque, par Gumilla, tom. 2. p. 13.
Nota. This author seems to be the only one who
approaches the truth, with regard to the slowness of these animals
[154] [back to page 153].

* It is alledged by the natives, that this
animal lives solely on the leaves of a certain tree, called in their
language Amahut. This tree is higher than any other in that
country. Its leaves are very small and delicate; and, because
the sloth is commonly found in these trees, they have given it the
name of Haut; Singul. de la France Antarc, par Thevet.
p. 100.--- The sloth lives solely on the leaves of trees, and the
highest branches serve him for a retreat; but it costs him two days
journey to arrive at them .. Neither caresses, threatenings, nor
even blows, can make him move quicker; Hist. des Indes, par
Massè, p. 71. Herrera, p. 252.  The
sloth is not so large, nor so rough as the tamanoir, or great
ant-eater ..He feeds upon leaves ..These animals do much
mischief to trees; after eating all the leaves of one tree, they
employ five or six days in descending it and climbing another,
however nearly situated; and, though plump and fat when they begin
their journey, the are reduced to skin and bone before they finish
it. They never abandon a tree till they have made it as bare as
it can be in the middle of winter; Dampiers
Voyage.They climb trees, but so slowly, that they are
easily taken. When seized, they make no resistance, and never attempt
to fly. If a long pole is presented to the sloth, he begins to
mount it; but the slowness of his motion is tiresome: When he
arrives at the top, he remains there, without taking the trouble of
descending; Voyage de Cayenne, par Binet, p. 341. --- The
sloths have four legs, which they employ only in climbing: When
perched upon a tree, they never quit it till they have eat the whole
leaves. They then descend, and mount another, the leaves of
which they devour in the same manner.We placed this animal on
the lowest sail of the fore-mast. It spent two hours climbing
to the scuttle, which a monkey would have accomplished in half a
minute. One would imagine that it moves by a spring, like the
pendulum of a clock; Travels by Woods Rogers [back
to page 157].

*I had a present of a living haut, which I kept
twenty-six days, during which he neither eat nor drank; Singular.
de la France Ant. par Thevet, p. 99 [back
to page 158].